Greenfield Threading
Greenfield Threading 285370 Spiral Point Tap 1/4-28 UNF 3 Flutes H5
A spiral-point tap cuts 1/4-28 UNF threads in through-holes with three flutes and a TiN-coated high-speed steel body
- H5 thread limit ensures precise 2B-3B fit
- Spiral-point design drives chips ahead for cleaner threads
- High-speed steel with TiN coating resists wear in production runs
- Three-flute geometry balances strength and chip clearance
- Right-hand UNF 1/4-28 cuts standard fine threads
Greenfield Threading Spiral Point Tap
This Greenfield Threading spiral point tap cuts internal threads in a 1/4-28 UNF size with three flutes and an H5 thread limit. The high-speed steel body carries a TiN coating for wear resistance during production threading tasks.
Plug-chamfer design starts easily in through holes
The plug chamfer helps the tap start straight in a through hole, while the spiral-point geometry pushes chips ahead of the flutes to reduce binding. Breakage usually occurs when the drilled hole is undersized or when cutting fluid is omitted during deep cuts.
Chips flow forward under sustained cutting
Because the spiral point forces chips forward, the flutes stay clear during long production runs and heat builds more slowly than with standard flute taps. The TiN surface maintains hardness at elevated temperatures so thread quality remains consistent across repeated holes.
Highlights
- H5 thread limit ensures precise 2B-3B fit
- Spiral-point design drives chips ahead for cleaner threads
- High-speed steel with TiN coating resists wear in production runs
- Three-flute geometry balances strength and chip clearance
- Right-hand UNF 1/4-28 cuts standard fine threads
Specifications
| Brand | CHICAGO-LATROBE |
|---|
Questions about this item
How do I confirm the tap cuts threads to the 2B-3B class of fit?
Check the finished thread with a GO/NO-GO gauge set for 1/4-28 UNF 2B-3B; the GO gauge should enter fully and the NO-GO gauge should not pass more than three turns.
What comes in the package and do I need a separate drill bit?
The box contains the spiral-point tap only; you must supply a 5.45 mm drill bit to produce the recommended 75 percent thread depth.
Which tap should I choose for a standard 1/4-28 UNF hole?
Select the H5 thread-limit version (part 285370) when the design calls for a 2B-3B class of fit in a through hole.
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